1. Field of the Invention
Propoxyphene finds wide use as an analgesic in that it affords pain relief while having fewer side effects than codeine. Propoxyphene finds a place in the battery of drugs employed for the medical treatment of people. Because of propoxyphene's effect on the central nervous system, the use of propoxyphene has become abused. That is, the drug has become sold on the street and is used in other than medicinal treatment. It has, therefore, become a matter of concern to detect those users of the drug, who use the drug without medical authorization.
There are a number of different ways for detecting the presence of a drug in urine. Some of these techniques employ chromatographic techniques such as vapor phase chromatography, thin-layer chromatography, and the like. These techniques depend upon the properties of adsorption of the drug of interest, which allow for the drug to be separated from other materials in the sample being tested. Another group of techniques rely on the ability of a receptor such as an antibody, to distinguish the molecule of interest from other molecules which may be present. These techniques are referred to as immunoassays since they depend on a mammalian immunological response for the production of the antibodies which recognize the compound of interest.
In producing antibodies, one normally conjugates a molecule which resembles the compound of interest to a large molecule which is antigenic. The resulting conjugate is then injected into an animal, normally a domestic animal, to elicit an immunological response with the production of antibodies which recognize the compound of interest.
In producing antibodies, there are a number of considerations as to the usefulness of the antibody composition in an immunoassay. The concentration of useful antibodies must be sufficiently high, so that upon dilution in the assay, there is sufficient antibody to provide for the necessary sensitivity. The binding constant of the antibody should also be high, so that large concentrations of antibodies are not required to ensure a reasonable amount of binding of any of the compound present to the antibody. It should be recognized that normally the concentrations of interest are only a few micrograms per milliliter or less so that one is dealing with extremely small amounts of the compound being assayed. In addition, it is desirable that the antibody have a certain degree of specificity. In some instances, only one compound is of interest. In other instances, the antibody should not only recognize the specific compound of interest, but also metabolites having similar structure, but differing in the presence or absence of a substituent.
2. Description of the Prior Art
U.S. Pat. No. 3,817,837 describes a homogeneous enzyme immunoassay technique, as well as enzyme conjugates for use in the assay. Included among potential conjugates are propoxyphene derivatives. U.S. Pat. No. 3,690,834 describes a homogeneous immunoassay employing a free radical detector. Included among potential reagents are spin labeled propoxyphenes.